This disclosure relates generally to a gas turbine engine, and more particularly to an attachment for a composite rotor blade of a gas turbine engine.
Gas turbine engines, such as turbofan gas turbine engines, typically include a fan section, a compressor section, a combustor section and a turbine section. During operation, air is pressurized in the compressor section and mixed with fuel in the combustor section for generating hot combustion gases. The hot combustion gases flow through the turbine section which extracts energy from the hot combustion gases to power the compressor section and drive the fan section.
Gas turbine engines typically include a plurality of rotating blades that either add energy to the airflow communicated through the engine or extract energy from the airflow. For example, the turbine section of the gas turbine engine includes a plurality of rotor blades that extract the energy from the hot combustion gases communicated through the turbine section to power the compressor section and the fan section. The rotor blades typically include an airfoil section and a root section that is mounted to a rotating disk. The root section may include a “fir-tree” shape, and the rotating disk may include a slot having a corresponding “fir-tree” shape for receiving the root section.
Gas turbine engine rotor blades made from composite materials are known and can provide significant weight and cooling air savings. Composite rotor blades have a high strength to weight ratio that allows for the design of low weight parts able to withstand extreme temperatures and loading associated with a gas turbine engine.
One drawback to composite rotor blades is that since the blades are often made of a laminated fiber or filament reinforced composite material, and the rotor disks are typically made from a metallic material, the transfer of forces and loads between the rotor blades and the rotating disk may damage the root section of the rotor blade. In addition, the machining of a traditional “fir-tree” shape on the root section may compromise the strength of a composite rotator blade when using composite materials, such as fabric materials and/or fibers which are layered and glued together with a matrix material.
Accordingly, it is desirable to provide an improved composite rotor blade that is high in strength and provides adequate attachment to a rotating disk.